Eruption Problems

Natal/Neonatal Teeth

Natal teeth refer to teeth present at birth. Neonatal teeth refer to teeth erupting within one month of birth. The teeth tend to have abnormal roots. Treatment is dependant on the mobility of the teeth and feeding problems. If the teeth are mobile with the strong possibility of aspiration, they should be extracted. If the mother finds breast-feeding painful because of irritation by the tooth on the breast, a composite material can be placed on the incisal surface of the tooth to reduce the sharpness of the tooth. More radical measures would include bottle-feeding the child or extraction.

Image: Natal/Neonatal Teeth

Over-retained Teeth

Over-retention of primary teeth is due to delayed resorption of the roots due to lingual positioning of the permanent teeth due to crowding of the permanent teeth, root canal obliteration (trauma) failure of endodontic obturation material to resorb, and bruxism. The timing of treatment is dependent on which arch is involved.

Image: Over-retained Teeth
In the mandibular arch, if the primary tooth is mobile allow the tooth to exfoliate on its own. However if the tooth is not exfoliated by age 8 or three quarters of the root of the permanent tooth is formed, the primary tooth should be extracted. Once the primary tooth is no longer present the permanent will migrate labially spontaneously.
Image: Over-retained Teeth - mandibular arch
In the maxillary arch, even if the primary teeth are mobile they should be extracted to prevent the permanent tooth from erupting in cross-bite with the mandibular incisor. If the permanent tooth erupts in cross-bite, orthodontic intervention will be necessary to move the tooth into its proper position, as interference by the mandibular incisor will prevent spontaneous labial migration.
Image: Over-retained Teeth - maxillary arch
If the permanent tooth is erupting labially, extraction of the primary tooth is not urgent.
Image: Permanent tooth erupting labially.


A diastema is defined as spacing between the maxillary central incisors. It is common and desirable in the primary and mixed dentition. The lack of a diastema in the primary and mixed dentition is indicative of potential crowding in the permanent dentition. The etiology of a large diastema (>2mm) is a deep bite, a tooth size discrepancy (length/width), a large frenum, and presence of a supernumerary tooth. Treatment may involve a combination of orthodontic treatment, veneers or crowns, and surgical removal of the enlarged frenum after completion of orthodontic treatment.

Image: Diastemas

Orthodontic Problems

An in depth discussion of orthodontic problems is beyond the scope of this course. However the practitioner should be aware that interceptive orthodontic treatment is initiated during the primary and mixed dentition. Waiting to refer the patient for orthodontic treatment until the permanent dentition is fully erupted is an invitation for extensive treatment that might have been avoided with an earlier referral. The practitioner should follow adage “When in doubt, send it out”.

Image: Teeth with orthodontic problems.

Ectopic Eruption

Ectopic eruption is a malposition of a permanent tooth bud resulting in the tooth erupting in the wrong place. The most common areas are the maxillary first molars, followed by the maxillary cuspids.

First permanent molar – Ectopic eruption is due to mesial positioning or inclination of the tooth into the second primary molar. This can result in delay of eruption of the first permanent molar and resorption of the distal root of the second primary molar. Treatment consists of:

  • Placement of separating elastics, brass ligature wire or orthodontic appliance to distalize the first molar.
  • Contour the distal of the second primary molar.
  • Extraction of the second primary molar and placement of a distalizing appliance.
Image: Ectopic Eruption - radiograph
Image: Placement of separating elastics, brass ligature wire or orthodontic appliance to distalize the first molar.

Cuspid – Ectopic eruption is due to the mesial inclination of the permanent cuspid becoming impacted in the palate or impacting on the root of the lateral incisor. A clinical indicator is distal tipping of the lateral incisor crown. Panoramic, periapical and occlusal radiographs are used to determine the position of the cuspid relative to the lateral incisor. Treatment consists of:

  • Extraction of the primary cuspid.
  • Orthodontic lassoing of the permanent cuspid.
Image: Cuspid ectopic eruption - radiograph
Image: Cuspid ectopic eruption
Image: Orthodontic lassoing of the permanent cuspid.


Ankylosis is an interruption of tooth eruption due to the formation a solid union between the root and bone. It is mostly seen in mandibular molars and in traumatized anterior teeth (For an in depth description the reader is referred to the CE course “ Management of Traumatic Injuries in Children’s Teeth” at Submersion is due to alveolar growth surrounding the tooth. In the posterior region the submersion of the ankylosed tooth may cause mesial tipping of the permanent first molar. Treatment:

Primary molars

  • Observe as the tooth may eventually exfoliate
  • If the ankylosed primary tooth is interfering with the eruption of the bicuspid extract the primary tooth and place a space maintainer.
  • If a permanent tooth is not present build up the primary tooth with composite of a stainless steel crown.
Image: Ankylosis - radiograph

Unequal Resorption

Unequal resorption of the roots of the primary molars results in over-retention of the teeth. If untreated there may displacement of the permanent tooth. Treatment consists of extraction of the primary tooth. As the permanent teeth may be close to eruption space maintenance may not be required.

Image: Unequal Resorption - radiograph

Congenitally Missing Teeth (anodontia, hypodontia)

Anodontia, the complete failure of teeth to develop, is extremely rare. Hypodontia (partial anodontia) is more common. The most frequently absent teeth in children are mandibular second premolars, maxillary lateral incisors and maxillary second premolars. The congenitally missing teeth may be bilateral or unilateral. If a primary tooth is missing the permanent tooth will usually be missing. However, even if a primary tooth is present a permanent tooth can be missing. Treatment:


  • In the primary or mixed dentition “Pedo” partial dentures can be placed to replace the missing teeth.
  • In the permanent dentition orthodontics, bonded prosthetics and implants are use to replace the missing teeth.
Image: Congenitally Missing Teeth (anodontia, hypodontia) - radiograph
Image: Congenitally Missing Teeth (anodontia, hypodontia)
Image: Congenitally Missing Teeth (anodontia, hypodontia)